This YouMoz entry was submitted by one of our community members. The author’s views are entirely his or her own (excluding an unlikely case of hypnosis) and may not reflect the views of Moz.

“Do not speak unless you can improve the silence”

I still see many blogs that use underscores in the URL -- ../this_is_my_post

But from an SEO perspective, we've always been told dashes are the way to go, since older programming languages and PHP use the underscore with variables...and then there's Matt's post from a while ago, and Matt's blog is as close to gospel as we SEO'ers get (though we should probably reconsider that at times).

"No one tests the depth of a river with both feet"

I decided to run a little test here at SEOmoz to gauge how effective each spacer was with Ask, Yahoo, MSN, and Google. SEOmoz seemed like the best place to run this test--it's a very visible site and I've spent a good deal of my time here writing posts and submitting comments, so there are many instances on the site where a link with the anchor text of my handle points back to my profile page. All I needed to do is measure the ranking of my profile page with the changes to the handle. Special thanks to Oatmeal for changing my nick for me twice.

*I should note that while SEOmoz has a good deal of inner linking with my name and profile, I doubt there are any links at all from outside the site to my profile with my name as the anchor text.

First, I had my handle changed from BudC to "Bud_Caddell" -- I let this sit for a while, then I did a rank test across the SEs for terms related to my name...

I waited another while, changed my handle to "Bud-Caddell" and ran another ranking test.. here are the results:

This is the effective change from going from "Bud_Caddell" to "Bud-Caddell" as my handle on SEOmoz

You'll see at Google, with the underscores, my profile didn't show up at all for "bud caddell" or 'bud caddell,' but when I made the change to dashes, my profile page immediately jumped up the results (within 3 days). Interesting enough, it looks like the change didn't affect the Ask or MSN results really, and Yahoo doesn't seem to like me at all (external linking deficiency?) or is incredibly slow to update their search data.

Questions I still have from this experiment..

We may know how search engines parse a page based on the underscore or dash, but how do they handle these characters as search queries? Could that be affecting the ranking of the above terms?

Is this also proof of Google outweighing external linking factors with the trust or authority of the domain?

Is it correct for Google to be toe'ing such a hard line on this issue -- shouldn't their algorithm be more about ranking the web as it is, not as it should be? Are the technical issues enough to warrant such a hard stance?

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Comments
31

Great follow up article, Bud! I think much of the dislike for using the underscore char comes from the way it was used in early programming days. As well, here's an interesting excerpt from IBM's web site on Host Names and the underscore character:

"Avoid using the underscore (_) character in machine names. Internet standards dictate that domain names conform to the host name requirements described in Internet Official Protocol Standards RFC 952 and RFC 1123. Domain names must contain only letters (upper or lower case) and digits. Domain names can also contain dash characters ( - ) as long as the dashes are not on the ends of the name. Underscore characters ( _ ) are not supported in the host name. If you have installed WebSphere Application Server on a machine with an underscore character in the machine name, access the machine with its IP address until you rename the machine."

Does the fact I described the above excerpt as "interesting" mean I am a geek? Hope y'all have a great weekend!

It's funny, I actually noticed that you changed your SEOmoz ID (I notice stuff like that), but I just thought that you were trying to stay fresh and mix it up a bit (maybe you were bored, or are very easily amused). It never occurred to me that it was an SEO experiment.

Are you using WebCEO? We bought that program at my last job and the more Clients I added the slower it went. Advanced Web Ranking at least let me backup and deletes certain clients.

I was excited about the software features first but, it promises integration but delivers it in a very poor way. Some of the features are great, like being able to add my own calculations for the page rank or importance in the Page Optimizer tool. But sadly you can only do one page at a time, which is a time killer for a large site.

Sorry if this is off topic... but I saw your posts research image (ball of twine) and I have been curious ever since.

Ya know, I only use it for Ranking Keywords across multiple engines and sometimes to see what pages are indexed as well. I don't really mess with the rest of the program very often, too clunky, too 'buy now for the better version'

I was just curious how many sites out are marketing towards words that are separated by an underscore.

I don't suspect many companies are trying to rank for 'blue_widgets' or 'blue-widgets', they are trying to rank for 'blue widgets' so why would they even use a dash or an underscore in their copy?

Your test is only changing the keyword in the copy and not in the URL since your URL is www.seomoz.org/users/view/22017 no matter what user name you are having Matt change it to.

It seems that you are trying to make the point that underscores are not good for file names (which I totally disagree with since my blog uses underscores and it ranks very well for many terms - look at the results for 'myspace comment spam' - they are in the URL separated by underscores and all words are highlighted by Google showing that they see them as independent words), but your test never has an underscore or hyphen in the URL in the first place.

Heck, take a look at the Digg URLs. They are separated by underscores and we all know that Digg doesn't have a problem ranking in the search results.

I also think underscores in the filename make it easier on the eyes to differentiate the words and thus cause people to see the keywords that they are looking for just a little easier (just my opinion b/c I like the way they read better personally). This is due to the fact that the underscore is actually longer meaning there is more separation between words.

I'm not trying to make any kind of blanket statement, this was just one test -- a test of dashes used only in anchor text (which isn't 100 logical I admit) -- it's good to get more real examples like you've listed.

A good follow up test might be using dashes and underscores in the URL itself -- any takers?

Bud I remember you mentioning the change in usernames here as part of this experiment, but I admit I had forgotten about it until reading now. Glad to see the post.

I took a very unscientific look last summer at domains where the words ran together compared to domains using the dashes. Hardly scientific like I say it was more me looking at search results and applying what I hope was logic to what I saw.

I think it fits somewhat with your experiment so here's the link if you're interested:

Interesting experiment, Bud. I've always heard people (both in the SEO and devleopment communities) say to use the "-" instead of the "_", but nobody ever says why. It's really interesting to know that the search engines might not treat "_"-separated terms as individual words.

I really don't know why they can't. It would seem just as easy to use an underscore as a separator as it would to use a dash. But all indications are that they don't parse on the underscore and so it gets seen as part of one long word instead of separating two distinct words.

shouldn't their algorithm be more about ranking the web as it is, not as it should be?

Good question - I wonder why they are taking any kind of a stance on this question. Perhaps it's because hyphens are easier to read as word separators (perhaps they know this from clickthrough rates etc.) and they are applying their knowledge / research across the rest of the web?

I've got a site using underscores - looked at where one of the product pages for it's main two word keyphrase was in SERP on G and for the keywords it just ain't there at all (G only returns 6 results for the keyword combination so not overly difficult to analyse).

Tried the keyphrase with the underscore instead of a space...bingo number one. OK no1 out of still half a dozen results isn't going to suddenly bring armies of customers - but no position at all sure as hell is a problem.

Google are effecively "giving away" higher positions to those savvy enough to use dashes. Matt basically told us all to do it years ago, those that listen will do better than those that don't. Agreed, this is pretty daft - the English language USES underscores as separators. The use of dashes is for splitting words in two, not separating different words. I could go on, but I spell colour properly so I don't really fit in with web standards anyways; gramatical correctness & the web are obviously separate beasts ;)